In vitro LHRH release: correlation with the LH surge and alteration by a mammary carcinogen.
The releasability of LHRH from neurosecretory terminals, as assessed in vitro by depolarization of hypothalamic synaptosomes with elevated K+, varies as a function of the time of day in parallel with the LH surge. Pretreatment of ovariectomized female rats with dimethylbenz(a)anthracene (DMBA) results in a blockade of the estrogen-induced LH surge and a blunting of LHRH release as measured in vitro. An examination of the LHRH release process revealed that K+-stimulated release of particulate LHRH was inhibited by DMBA pretreatment while basal release of particulate LHRH and both basal and K+-stimulated release of soluble LHRH were not altered. These results suggest that release of particulate LHRH is closely coupled with the estrogen-induced LH surge.
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000494:pharmacology*; D000818:Animals; D001551:Benz(a)Anthracenes / Q000494:pharmacology*; D002369:Castration; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000378:metabolism*; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced; D011188:Potassium / Q000494:pharmacology; D051381:Rats
D001551:Benz(a)Anthracenes; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D015127:9,10-Dimethyl-1,2-benzanthracene; D007986:Luteinizing Hormone; D011188:Potassium